Ship hull construction

ABSTRACT

Centrifugal force is used to reduce or eliminate water pressure on a ship bow. A hull design for a ship includes a bow whose front portion is rounded or otherwise curved and is preferably an arc of an imaginary circle whose diameter is at least one-fourth of the width of the hull. In the curved bow of the invention, the water moves in circles and semi-circles, which causes centrifugal force to pull the water away from the bow. In contrast, in the standard type of straight tapered and pointed bow the water is in constant pressure on the sides, so that the greater the speed the higher is the pressure, which is the reverse of the curved bow of the invention wherein the pressure decreases with increase of speed. Bows can be made, under the invention, in graduated shapes from a rounded corner to a semi-circle. Tests with models have shown that the curved bow permits equivalent models to be propelled more than twice as fast as models having the conventional straight-sided bow.

United States Patent n91 Wendorf l l SHIP HULL CONSTRUCTION Ovaldo Wendorf, 325 Broadway. Newark, NJ. O'llO4 [22] Filed: Feb. 8, X974 [21] Appl. No: 440,808

[76] Inventor:

Primary E.raminerTrygve M. Blix Assistant Examiner-Charles E. Frankfort Attorney, Agent. or Firm-Eliot S. Gerber 1 June 10, 1975 [57] ABSTRACT Centrifugal force is used to reduce or eliminate water pressure on a ship bow. A hull design for a ship includes a bow whose front portion is rounded or other wise curved and is preferably an arc of an imaginary circle whose diameter is at least one-fourth of the width of the hull. In the curved bow of the invention. the water moves in circles and semi-circles, which causes centrifugal force to pull the water away from the bow. In contrast, in the standard type of straight tapered and pointed bow the water is in constant pressure on the sides, so that the greater the speed the higher is the pressure, which is the reverse of the curved bow of the invention wherein the pressure decreases with increase of speed. Bows can be made. under the invention, in graduated shapes from a rounded corner to a semi-circle. Tests with models have shown that the curved bow permits equivalent models to be propelled more than twice as fast as models having the conventional straight-sided bow.

1 Claim, 4 Drawing Figures PATENTEDJUN 10 ms FIG. I

fi z/ae Aer) SHIP HULL CONSTRUCTION BACKGROUND OF THE INVENTION The present invention relates to ship design and more particularly to the form of the hull of a steel ship.

At the present time one of the major objectives of the design of hull forms for ships, and particularly for steel merchant ships, is to obtain the proper hydrostatic and hydro-dynamic characteristics in view of the need of the ship for stability, steering and maneuverability performance. Those characteristics must take account of the influences of weather, safety and other factors. In terms of efficiency, that is, the relationship of the ships speed to the force of propulsion, the major factor is water and wind resistance. The total resistance of ships is made up of their skin frictional resistance in the water and resistance to wave-making, eddy resistance and air resistance. The two major factors are the skin frictional resistance and wave-making resistance, both of which are resistances to water. Steel merchant ships at the present time have a hull shape in which their bow comes to a point, that is, the two sides of the ship meet in a sharp angle to form the bow. Certain types of ships, particularly oil tankers, have a bulbous protrusion at the bottom of the bow, but above that bulbous protru sion their bows are also pointed.

It is an objective of the present invention to provide a novel hull form and more particularly a novel form for the bow of steel merchant ships, although the bow form may be used on other types of ships, including war ships.

It is a further objective of the present invention that the novel bow of the present invention will reduce the resistance of ships to propulsion through the water and particularly reduce the skin water frictional resistance and the wave-making resistance.

It is a further objective of the present invention that for a given speed and a given size of ship, a smaller propulsion force may be used. Consequently, a saving in the cost of fuel may be effected. Or alternatively, that for the same size of propulsion plant the speed of the ship may be increased as compared to those ships having the bow constructions of the prior art.

BRIEF SUMMARY OF THE INVENTION In accordance with the present invention, a hull form is provided in which the bow has, below the water line, a curved shape, for example, a rounded shape, as seen in top cross-section, as contrasted to the pointed or angled shape of the prior art. It is believed that the round shape of the forward portion of the bow of the present invention will act to decrease the wave-making resistance on the ship. As a hypothesis, it is possible that such an advantage is obtained by the centrifugal action, that is, the outward moving action of the water away from the imaginary line through the center of the ship in the direction of its travel. It is also believed that an improvement in skin frictional resistance results from the curved bow shape of the present invention.

The present invention is applicable to ships of all types as it only involves a re-structuring of the bow. For example, ships having a poor bow construction may be altered by the addition of a false bow, giving the round or curved shape of the present invention.

In addition, the curved bow of the present invention provides additional cargo space as compared to the angled how of the prior art. It will be noted that the elevation profile or sheer plan of the ship is not affected. That is, the ship as seen in side view would appear to be the same. However, as shown in the enclosed drawings, the bow below the water line is rounded as seen in top cross sectional view.

The following detailed description is of the inventors best mode of practicing the invention, the detailed description to be taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. I is a side plan view of a ship utilizing the bow construction of the present invention, the ship, for purposes of illustration, being shown as an oil carrier;

FIG. 2 is a top cross-sectional view taken of the bow of a ship of the prior art, the said cross-section being taken below the water line;

FIG. 3 is a crosssectional view taken along line 33 of FIG. 2 and is a cross-sectional view of the bow taken below the water line of the bow of the present invention; and

FIG. 4 is a perspective view, partly in cross-section, of an alternative embodiment of the present invention.

As shown in FIG. 1, the boat 10 of the present invention is conventional in all respects, except for its bow portion 11. The boat is a merchant ship of steel construction and includes the steel side plating 12, a relatively flat keel l3 and a propeller shaft 14 and a propeller 15.

As shown in FIG. 2, the prior art bow construction is pointed (as seen in top view cross-section), that is, the left side of the ship 20 meets the right side of the ship 21 at a point 22. Although the angle between the sides 20 and 21 varies depending upon the size and the type of the ship, they would nevertheless, despite the difference in angle, meet at a relatively sharp point.

In contrast, the left side 30 of the ship of the present invention, as shown in FIG. 3, is curved, as is the right side 31. These two curved sides blend gradually to form a circular and curved arc portion 33 which is the bow of the ship. The bow arc portion is welded or riveted to the side plates 30, 31. Preferably the bow 33 is a segment of a true circle. That is, as shown in the dashed line 34, the are 33 may be continued in an imaginary fashion to form the dashed line 34, with the dashed line 34 and the are 33 forming a complete circle. The imaginary circle has a diameter which is at least one-fourth and less than onehalf of the width of the hull, measured on a plane through the circle, i.e., a horizontal plane. It will be understood, however, that the arc portion 33 is a steel plate which is welded, riveted or otherwise fastened to the steel platings forming the sides 30 and 31. As in conventional ships, the keel of the ship of the present invention may be flat or alternatively may be rounded. In addition, as in conventional modern oil carrying ships, the bulbous protrusion may be formed at the bottom of the bow.

It is the inventors hypothesis that the movement of the curved bow through the water will lessen both water wave-making resistance and water skin resistance. This hypothesis has been tested using a series of small models. Using the same propulsion on models having an angled bow as in the prior art, as opposed to models having an arcuate bow as in the present invention, it has been found that higher speed may be obtained using the arcuate bow with the same propulsion force and under the same exterior conditions and the same load.

Modifications may be made in the present invention within the scope of the subjoined claims. For example, as shown in FIG. 4 the bow (as seen in top crossseetional view) is not a segment of a circle but yet is curved (top cross-sectional view) in the plates which meet the front of the bow and the front of the bow itself is curved (top cross-sectional view) Having thus described the invention, what is claimed l. The hull of a ship wherein below the water line the forward end portion of the bow is curved as seen in top cross-sectional view, wherein the said curve is a portion of a circle so that the bow is rounded, wherein the diameter of the said circle is at least one-third in length of the width of said hull at the hulls widest part, wherein said curved portion is a curved steel plate, the hull is constructed of steel side hull plates, said curved steel plate is connected to said side hull plate, and wherein the front of the bow below the water line is substantially vertical as seen in side view. 

1. The hull of a ship wherein below the water line the forward end portion of the bow is curved as seen in top cross-sectional view, wherein the said curve is a portion of a circle so that the bow is rounded, wherein the diameter of the said circle is at least one-third in length of the width of said hull at the hull''s widest part, wherein said curved portion is a curved steel plate, the hull is constructed of steel side hull plates, said curved steel plate is connected to said side hull plate, and wherein the front of the bow below the water line is substantially vertical as seen in side view. 